What is the purpose of the $ operator in a javascript function declaration?

Question

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Why would a javascript variable start with a dollar sign?
Can someone explain the dollar sign in Javascript?

I was looking at a js tutorial where several of the functions where declared with a $ in front of them. I have done some on-line searching but can find no reference to this. Here is an example I created myself:

var $x = function(q)
{
  return q*q;
}

var $y = function()
{
  alert($x(10));
}

When I call $y from a webpage I get an alert with 100, which is what I expect. So, what, if anything, is the $ for?

It's a valid character. They could have called them `Cx` and `Cy`. — xanatos, Sep 03 '11 at 19:54
May be this answer can give you some insight http://stackoverflow.com/questions/3155979/why-does-several-javascript-libraries-use-for-one-or-other-use — sushil bharwani, Sep 03 '11 at 19:55

score 2 · Answer 1 · answered Sep 03 '11 at 19:54

2

I don't think $ means anything special, the tutorial just decided to name the function $x and $y

answered Sep 03 '11 at 19:54

awesome

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score 1 · Answer 2 · answered Sep 03 '11 at 19:54

1

It doesn't mean anything special unless you've included jQuery. Generally, I've seen $ used in the beginning of variables to mark them as global variables.

answered Sep 03 '11 at 19:54

VNO

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score 0 · Answer 3 · edited May 23 '17 at 12:29

$ is one of the allowed signs for names of variables in JavaScript. It is not an operator.

As some other answer on SO mentioned, allowed characters are: [a-zA-Z_$][0-9a-zA-Z_$]*.

So, this is not an operator, and can be used to distinguish some variables from other variables.

When it comes to single dolar sign ($, without any other letter), this is common as alias for jQuery function, if you have installed jQuery and stick with default settings.

score 0 · Answer 4 · answered Sep 03 '11 at 20:01

0

In this particular case, serves no purpose. You can remove it an simply do y(10); or x(10);

For example Microsoft introduced $find as a shorthand for document.getElementById

answered Sep 03 '11 at 20:01

Icarus

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What is the purpose of the $ operator in a javascript function declaration?

4 Answers4